Soap of all kinds, disposable diapers, baby wipes, feminine hygiene products, baby formula, cooking oil (especially if things are so bad there are bulk-grain handouts from .gov), sugar, salt, trash bags, charcoal briquettes, CLEAN/un-used 5gal buckets.
These are all things that are dirt cheap now, can keep for a long time, and are invaluable if SHTF.